Week 5 Quailty if Pastures

Question 1

Define DMD, OMD, ME and Crude Protein

Answer 1

Dry Matter Digestibility - % DM retained by the animal

Question 2

Describe why plants vary in quality

Answer 2

C3 vs C4
C4 - bundle sheath and extra lignification, more hemicellulose
C3- Protein content

Legumes are lower in cell wall material than grasses

Legume Fibre- Shortwer digestion time in rumen

Tropical species have higher fibre content

Age: Soluble content decreases, cellulose, hemicellulose, ligin increase.
Lignification doesnt occur in legumes

Stems lignify much faster than leaves

Higher up the plant the more digestible it is

Question 3

Inc. Age =

Answer 3

Inc fibre

Dec. Protein and quanlity

Question 4

Outline the factors that affect potential animal intake and actual daily intake

Answer 4

Potential Daily Intake
Size, Type, Level of production

Actual Daily Intake
Enviro, Pasture Attributes (quality, sward structure, Availability, Supp feeding)

Question 5

Explain the effect that digestibility has on animal intake and why

Answer 5

Dec. quality of feed = long digestion time = less grazing

Water abover 85% = dec. intake

Question 6

Explain the effect that digestibility has on animal intake and why

Answer 6

Inc. Sward = inc. DM per bite

Inc. Sward = dec. bites per minute

Hrs grazing reduces with inc sward

Kg inc. with sward

Question 7

Short grass =

Answer 7

Cannot get enough intake

Highest intake is high grass in clumps

Question 8

Explain why the quality of the pasture that the animal intakes does not match the quality of the pasture

Answer 8

Selective grazing

Question 9

Inc. LAI =

Growth max=

Answer 9

More PSN
Actual DM in paddock depends on how much is lost in respiration

High LAI but also higher death

Question 10

Define stocking rate, grazing pressure, carrying capacity and DSE

Answer 10

SR- Number of animals per area of land (DSE)

G.P- Number of animals per nit of forage

Carry Capacity- SR @ optimum grazing pressure

Question 11

Under continuous grazing describe the different optimum LAI for gross photosynthesis, dry matter production and animal intake

Answer 11

Gross PS5N = Highest LAI
DM production = 5 (reaches 90% max)
Animal Intake 2.5

Question 12

Describe what happens to pasture growth rate when pastures are over or under stocked

Answer 12

Over- Annuals and less palatable species are favoured

Under- Legumes and other prostate species dont compete well

Question 13

Explain the effect off stocking rate on individual animal production

Answer 13

High SR limits individual intake, Dec. Individual wool, lwtgain, milk production, reproduction rate

Question 14

Describe the effect that stocking rate has on profitability and risk

Answer 14

Max profit= production per Ha not per head

SR and Profitability are closelty related

Inc. SR increases riask, profitabilirty is somewhere inbetween

Question 15

Describe the different types of grazing management systems

Answer 15

Continuous Stocking - set number

Intermittent
Rotational - series of paddocks grazed in seq
Time Control - Many sibdivisions
Strip grazing - Access to small % of strip using elctric fence
Strategic Grazing - Uses logical stocking to manipulate pasture compesition
Mob- large number to reduce weeds
Creep - Young stock in area before older
Deffered- Area kept free of livestock for a period

Question 16

Outline Phalaris grazing management and the effects of continuous versus rotational grazing

Answer 16

Rotation = persistence and basal cover
Rotational grazing favours phalaris
Critica period is Autumn/winter

Question 17

Factors affecting how long paddock will lastq

Answer 17

Pre Grazing DM
Pasture growth rate
Post grazing residue
Wastage
Animal Requirement

Question 18

Estimating DM on Farm

Answer 18

MLA Ruler (1200-2000) perfect
Rising Plate meter
By eye

Question 19

Estimating Pasture growth rate

Answer 19

Average Growth rate charts

Pastures from space

Question 20

Wastage level

Answer 20

Trampling 15-40%

Increases in wet condiditonds and set stocking

Question 21

Utilisation

Answer 21

Green leaf pasture loss over the summer
Most lost in Spring
Dairy (65-80%) utilisation
Dry sheep Farm less than 50%